This invention relates to configuration of two antennae with signal isolation between them, and more particularly to an antenna configuration for full duplex operation with a transmitting and a receiving antenna on a common mast. It is a frequent requirement that radio equipment at one location be operated with two antennae, as for full duplex operation with a transmitter and receiver operating simultaneously at closely spaced frequencies, or two receivers operating simultaneously. One known configuration has the two antennae elements at right angles for crosspolarization operation, with one vertical and one horizontal, or each at a 45.degree. angle to a ground plane. It is also possible to stack two ground plane configurations vertically, sometimes with the lower configuration inverted. One disadvantage of these prior art arrangements is the amount of space, or overall size, of the resulting configuration. Also the amount of isolation might not be as sufficient for convenient operation.